fisher



Nov. 1,1927.

H. J. FISHER TELEPHONE SYSTEM Filed March 8. 1926 2 Sheets-Sheet l //7venfo/t Nov. 1, 1927. 1,647,286

H. J. FISHER TELEPHONE SYSTEM Filed March 18. 1926 2 sheets-sheewPatented Nov. 1, 1927.

UNITED STATES PATENT OFFICE.

HAROLD T. FISHER, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO BELL TELEPHONELABORATORIES, INCORPORATEDyOF NEW YORK, N. Y., A CORPORATION OF NEW'YORK.

TELEPHONE .SYSTEM.

Application filed. March 18, 1926. SerialNo. 95,582.

This invention relates to telephone transmission lines. and moreparticularly to arrangements for interconnecting such lines to repeatercircuits and apparatus.

In systems of this type, an ordinary or control operator receives acallrequiring interconnection between two transmission lines, which need tobe coupled through repeater apparatus. This operator communicates with aso-called repeater operator over an ordinary call circuit requesting herto interconnect the two lines through a cord circuit containing repeaterapparatus. The repeater operator thereupon completes the r connectionand makes certain adjustments to regulate the transmission volume in accordance with the particular transmission lines employed. Thereupon herduties cease and the control operator assumes control of the connection.A. system of this general character is disclosed in the Patent No.1,635,227, issued to S. P. Shackleton and L. L. Glezen July 12, 1927.

It is an object of this invention to further improve systems of thistype by providing means in the control operators cord circuit for moreefficiently controlling and supervising an established connection. Inaccordance with this object means are provided for talkingfrom thecontrol operators position directly out on a transmission line ratherthan through a devious path including part of the repeater equipment andfor ringing directly out on a transmission line rather than relaying theringing current around the repeater equipment.

A further object is to provide for a more eiiicient control by thecontroloperator of the use of the repeater apparatus during theoperation of the system so that the repeater apparatus will notinterfere in any way with the transmission eiiiciency of the connection.

Inaccordance with one feature of the invention meansis provided wherebythe repeater apparatus itself may be disconnected when the controloperator desires to establish a talking connection over either one ofthe two lines or when she desiresto signal out over either one of thelines.

Another feature is the provision of means whereby incoming signa lsfromeither one of the lines are relayed directly to the control cperatorscord circuit.

Another feature is the provision of means whereby the repeater apparatusitself is disabled during all switching operations on the part of thecontrol operator relating to the supervision of a connection.

The accompanying drawings illustrate a preferred form of the invention.Fig. 1 shows portions of the incoming ends of two transmission linesthatmay be connected by means of the control operators cord circuits oneofwhich is shown in this figure and embodies certain features of theinvention. In Fig. 2 are shown the usual twin jacks and circuitarrangement which are associated with the incoming ends ofthesetransmission lines and by means of which a connection may beestablished through repeater apparatus. This figure also shows arepeater cord circuit embodying certain other features of this inventionwith the usual twin plugs whereby the cord is connected to thetransmission lines Referringnow to the drawings in more detail. it willbe observed that the incoming end of transmission line A is providedwith ajack 1 for the use of the control operator and twin jacks 2 and 3for use by the repeater operator, while the incoming: line B issimilarly provided with the jack 5 for use of the control operator andtwin jacks 6 and 7 for the use of the repeater operator. The controloperator may establish a connection between jacks 1 and 5 by means of a.cord circuit such as G. Cord circuit C is equipped with plug 10 forinsertion in iack 1 and plug 11 for insertion in jack 5. The twin jacks2 and and 6 and 7 usually terminate at a repeater operators positionwhere the repeater operator is equipped with a repeater cord circuitsuch as D. The cord circuit D is equipped with twin plugs 12 and 13 forinsertion in twin jacks 2 and 3, respectively, and twin plugs 15 and 16for insertion in jacks 6 and 7 respectively. Repeater cord circuit D isfurther equipped with a standard repeater equipment E merely indicatedby means of a box as its construction is well known in the art. Thisequipment is for transmission between line B and line A. The cordcircuit D is also equipped with another standard repeater equipment F,also-represented by means of a box for transmission from line A to lineB. It will be noted that the cord circuit D is further equipped with again control circuit at G for right to left transmission and anidentical gain control circuit H for left to right transmissioin To moreclearly bring forth the various features of this invention, a detaileddescription will now be made of the establish-' ing of a connection fromline A to line B. The first step for accomplishing this is, after thecalling operator on line A has caused the lighting of the usual linelamp (not shown) associated with jack 1, to insert plug 10 into jack 1.A. circuit is thereby completed as follows: battery to winding of relay20, sleeve terminals of plug 10 and jack 1, relay 21 to ground. Thiscauses the operation of relays 20 and 21. Relay 20 in operating closes acircuit for the operation of relay 23 over a circuit as follows:battery, armature and front contact of relay 20, winding of relay 23,armature and back contact of the alternating current responsive relay 26to ground. It willbe noted that circuits are also completed forsupervisory lamp 22 and relay 84; but as relay 23 is fast in operatingand relay 84 is slow in operating this latter relay and the supervisorylamp 252 do not have sufiicient time to become actuated before thecircuits therefor are broken at the armature and back contact of relay23. The control operator now operates the talking key 24L to include inan obvious manner her telephone set not shown but connected at 25. inthe circuit to thecalling subscriber.

The control. operator now communicates with the calling operatorconnected to line A and receives the number desired. Upon receiving thisnumber the control operator in serts plug 11 of cord circuit G into jack5 of line B, which is assumed to be the line mentioned. A circuitisthereby completed from battery through the winding of relay 29, windingof relay 30, winding of relay 20, sleeve terminals of plug 11 and jack5, relay 31 to ground. This circuit causes the operation of relays 29,30 and 31. The operation of relay 29 closes an obvious circuit for relay32 which in operating completes the tip conductor of cord C, so that theconnection through this cord circuit is now established from line A toline B.

Relay 30 in operating opens the circuit bridging relay 34; across thetalking conductors of cord circuit C; the purpose of this will behereinafter described.

If. a repeater apparatus is desired in this connection the controloperator now requests the repeater operator over the usual call wirecircuit to insert a repeater between the two lines. v The repeateroperator in complying with this request inserts the twin plugs 12 and13. and 15 and 16 of repeater cord cir cuit D into the twin jacks 2 and3. and (i and 7, respectively. The first result of this action is thatthe relays 35 and 36 are respectively operated. The circuit for relay235 may be traced as follows: battery. armature and front contact ofrelay 21. winding c relay 35, upper closed contacts of jack Q l ground.The circuit for relay 36 may be traced from battery, armature and frontcontact of relay 31, winding of relay Pit), upper closed contacts ofjack 6 to ground. The operation of these relays causes obvious circuitsto be closed for their respectively associated relays 38 and 39. Theoperation of the relays 35 and 36 switch their associated lines from thecontrol operators cord circuit to the repeater opcratoii"s cord circuitand at the same time connect the tip and ring eonductors from thecontrol operators cord to the sleeves of jacks 2 and 3. and 6 and 7. Theoperation of relays 38 and 3S) removes the short circuits around wellknown networks indicatedmerely by boxes 40 and 451. so as to includethese networks for lines A and B respectively across the tip and ringtermina s of jacks 3 and 7.

The repeater apparatus will now be connected into the circuit betweenthe lines A and B by the operation of the key This key is so arrangedthat the contacts 414 will always operate upon the actuation. of the keywhereas the contacts 4-5 and 4G or 47 may be successively operated. Thisis a standard well known arrangement for regulating the usual automaticgain control circuits to ad just the transmission requirements fordifferent lines. For example, if merely contact is operated relays 50and 51 are oper ated to establish certain control conditions. whereas ifkeys at) and 47 are also operated. the corresponding relays 52. 54- andare correspondingly operated to establish certain other conditions. Asthe construction of the grain control circuits forms no part of theinvention, no further description will be made thereof. The operation ofkey 44 closes a circuit for the operation of relays 57, 58, 59 and 60 asfollows: battery, winding of relay 58, winding of relay 57. also aparallel circuit from battery. winding of relay 60, winding of relay5!), arniature and back contact of relay 6?, armature and back contactof relay 64:, key 44- to ground. It will be noted that relay will alsooperate in an obvious circuit on the actuation of key 44 to prevent theoperation of relay 62 the purpose of which will be hereinafterdescribed. The operation of relays 58 and 60 closes a circuit for theoperation of relay (31 that may be traced as follows: battery winding ofrelay til. right hand armature and back contact of relay (32. outer lefthand armature and front contact: of relay 60, outer right hand armatureand lll pgn

front contact of relay 58,armature and back contact of relay 63,armature and back con-- tact of relay 64: to ground at key 44;. Theoperation. of relay 6]. as noted removes the short circuit across thetip and ring conductors for the repeater equipments E and F, while therelays 57, 58, 59 and 60 include these equipments in the connection. Thecircuit for the repeater equipment F from line A to line B may now betraced as follows: tip conductor of line A, upper inner armature andfront contact of relay 35, tip terminals of jack 2 and plug 12, innerright hand armature and front contact of relay 58, transformer 65. gaincontrol circuit H and depending on the operated or non-operatedcondition of relays 51, 53 and 55 through the left hand armatures andfront contacts of one or more of these relays, to include or removecorresponding portions of the network associated with this gain controlcircuit, to the tip conductor leading to the repeater equipment Fthrough the usual in put and output circuit thereof through windings oftransformer 67, back over the ring conductor through the output andinput circuits of the repeater equipment F, over the ring conductor tothe gain control circuit H,

. the right hand armatures and front contacts of one ormore of therelays 51, 53 and to the transformer 65, left hand armature and frontcontact of relay 58, ring terminals of plug 12 and jack 2, lowerarmature and front contact of relay 35 over the ring conductor of lineA. The other side of the circuit from line B may be traced as follows:tip conductor of line B, upper inner armature and front contact of relay36, tip terminals of jack 6 and plug 15, inner left hand armature andfront contact of relay 60, transformer 67, ring terminals of plug 16 andjack 7, network 41, tip terminals of jack 7, plug 16, transforn'ier 67,right hand armature and front contact of relay 60, ring terminals ofplug 15 and jack 6, lower armature and front contact of relay 36 throughthe ring conductor of line B. It will thus be seen that the operation ofthe above mentioned relays includes the repeater equipment F, thetransformer 67, the automatic gain control circuit H and the network 4-1in the connection for transmission from line A to line B. Similarly therepeater equipment E, the transformer 65, the automatic gain controlcircuit S and the network 4-0 are included in the connection fortransmls sion from line B to line A. This latter circuit is not outlinedas it can readily be traced in the same manner as the circuit for therepeater equipment for t-ransn'iission in the opposite direction.

If the control operator ha, already nailed over theline B, theconversation between the parties at either end may now take place overthe established connection. However, itis sometimes desirable to ringover the line after the connections through the repeaters have beenestablished and the operation of the circuit in this connection will.now be described.

, To ring the party on line B the control operator operates ringing key70. It will first be noted that the operation of this key suppliesbattery from the midpoint of the secondary winding of transformer coil73 to the tip and ring conductors in parallel, tip and ring terminals ofplug 11 and jack 5. upper inner mal'rediefore-break contacts and lowermake-beforebreak contacts of relay 36, sleeve terminals of jacks 6 and7, and plugs 15 and 16 through the retardation coil 75 over the singlelead connected at the center of the winding of this coil, through thewinding of relay 64, 1nake-before-break contacts of relay 62 to ground.This circuit causes the operation of relay 64:, which in operating opensthe energizing circuit for relays 57, 58, 59 and 60. The release ofrelays 60 and 58 causes the release of relay 61 so that the repeaterequipments F and E, the transformers 65 and 67 and the gain controlcircuits H and S are now disabled by being short circuited through thecontacts of relay 61. On the release of relays 59 and 60 current fromthe ringing source 72 is transmitted through key over the sleeveterminals of jacks 6 and 7 and plugs 15 and 16, to upper and lowerarmatures and back contacts of relay 59, make-before-break contacts ofrelay 60, tip and ring terminals of plug 15 and jack6, upper inner andlower armatures and front contacts of relay 36 to the tip and ringconductors of line B. It is noted, therefore, that the operation of ringing key 70 will not only cause ringing current to be transmitted to theline B, but the repeater equipment in the cord circuit D will also bedisabled or eliminated from the line. On the release of ringing key 70the circuits will be restored to their previous condition, that. is,relay 6% will release and the various relays connecting the repeaterequipment into the cord circuit will be operm ated.

If the control operator desires to talk over line B, she may operate hertalking key 24 and in this case the repeater equipments will also beeliminated from the cord circuit D. It will be noted that on theoperation of key 24 a battery connec'ion will be established throughres'stances 7 6 to the tip and ring leads in parallel through thecontacts of key to the tip and ring conductors of the cord circuit C tocause the operation of relay 6 1- to eliminate the repeater equipmentsin the same manner as when the ringing key 70 was operated. In this caseit may be desirable to operate a splitting my 78 to prevent the party online A from hearing the conversation.

lid

Similarly, if the control operator desires to communicate with the partyon line A she will operate the talking key 24: to connect the telephoneset 25 to the line and eliminate the repeater equipment from the cordcircuit D and in this case the splitting key 71 may be operated.

It will be noted that the cord circuit C is also arranged so that thecontrol operator may ring over line A. In this case she may operateringing key 75 and the operations are the same as when she operatesringing key 70 except off course that current from ringing source 76 istransmitted tothe line A and relay 63 is operated in place of relay 64from the battery at the mid-point of repeating coil 78 to eliminate therepeater equipment.

If either of the parties on line A or B desires to call the controloperator the incoming ringing current, say, for example, from line B,will cause the relay '79 to be operated over a circuit as follows:through the tip and ring ot' the conductors oi? line 1" upper innerandylower armatures'and front cont acts oi? relay 36, tip and ringterminals of jack 6 and plug 15, inner left hand and right handarmatures and front contacts of relay 60 through the windings of thealternating current responsive r-elay T9. The operation of relay 79opens the circuit for relay S0. The release of relay 8O closes a circuitfrom the ground at key 4 1- for the operation of relay 62-. Theoperation of relay 62 causes the release of relay 61 by the opening ofits circuit through the right hand armature and back contact o't thisrelay. The release of relay ()1 short-circuits the repeater equipmentsduring the remainder of the incoming ringing signal. The operation ofrelay 62 also removes ground from-the windings of relays 6 and 63, thuspreventing the accidental operation of these relays during the incomingsignal. The operation of this relay 62 also causes the operation ofrelay 82 in an obvious circuit. The operation of relay 82 connectscurrent from a ringing source 83 to the cord circuit D so that currentfrom this source will now be transmitted both through the sleeveterminals of plugs 15 and 16 and jacks 6 and 7 through the tip and ringterminals of jack 5 and plug 11 and through the sleeve terminals ofplugs 12 and 13 and jacks 2 and 3 through the tip and ring terminals ofjack 1 and plug 10 through the windings of alternating currentresponsive relay 26 in the control operators cord circuit C. Theoperation of relay 26 releases relay 23 thereby causing the operation ofrelay at from the battery at the armature and front contact of relay 20through ,the normally closed contacts of talking key 24; to ground. Therelay S4: establishes a locking circuit for itself through its armatureand front contact independent arness of the armature and back contactof: relay Lamp 22 is also operated in this circuit through the armatureand back contact of relay 23 or through the armature and front contactof relay 84 to ground at key let.

It the party on line A desires to ring the control operator, theprocedure is practically the same except that instead of relay 7S) operating, relay 85 will ope ale to open the circuit for relay 80 and thefunctioning of the circuit from there on is the same as when the partyon line B rings the toll operator that is, lamp is lighted in eithercase. The operation oi? lamp 22 thus indicates to the con trol operatorthat the party on either line B or line A desires to communicate withher. it, however, on the receipt of ringing cur rent from the party online B key 71 should be operated lamp 86 is lighted to indicate that thesignal originated from line B.

At the completion oi a call which may also be indicated by the lightingot a lamp the control operator will remove the plugs 10 and 11 fromjacks l and 5 respectively, thus causing the relays in this cord circuitC to be restored to normal position. The re moval of the pla s of thiscord circuit from lines A and B naturally causes relays 35 and 36, and3S and 39 to be returned to normal condition. The release of the relays38 and 39 short-circuits the "conductors to the net works 40 and 41 andthe release of these relays also connects battery to the tip and ringterminals of plug 3 and jack 13 and plug 7 and jack 16. This connectionto battery causes the operation of relays 88 and 89. The release ofrelays 38 and 39 also shortcircuits the line and network windings ol theoutput transformer in the repeater thereby preventing the repeater fromsinging due to the unbalance caused by the network being still connectedto the transformer alter the line has been disconnected by the releaseof relays 38 and 39. The circuit t'or relay 88 may be traced as follows:battery, make-beforebreak contacts of relay 38, tip and ring terminalsof jack 3 and plug 13 in. parallel through the winding of relay S8 toground. The operation of relays 88 and 89 closes an obvious circuit fora supervisory lamp 90, which in lighting indicates to the repeateroperator that disconnection is desired. The repeater operator nowimmediately removes the twin plugs 13 and 1st. and 15 and 16 from thejacks 2 and 3 and 6 and 7, respectively, and the relays in the repeatercord circuit D return to normal condition.

lVhat is claimed is: l

1. In a telephone systen'l, lines, a link circuit for establishing aconnection between two of said lines. a second link circuit forconnecting said lines, a repeater associated with said second linkcircuit and normally disconnected therefrom means in said second linkcircuit for connecting said repeater in theconnection between saidlines,a key in said lirstmentioned link circuit, and means responsive to theoperation of said key for disconnecting saidniepeater from theconnection between the lines.

2. In a telephone system, lines, a link circuit for establishingaconnection between two of said lines, a second link circuit forconnecting said lines, a repeater associated with said second linkcircuit and normally disconnected therefrom, means in said second linkcircuit for connecting said repeater in the connection between saidlines, a telephone set, means for connecting said telephone set to saidfirst mentioned link circuit, and means responsive to the actuation ofsaid last mentioned means for disconnecting said repeater from theconnection between said lines.

3. In a telephone system, lines, a link circuit for establishing aconnection between two of said lines, a second link circuit forconnecting said lines, a repeater associated with said second linkcircuit, means responsive to the connection of: said second link circuitto said lines for automatically excluding' the first mentioned linkcircuit from the connection between said lines, neans in said secondlink circuit for including said repeater in the connection between saidlines, a

key in said first mentioned link circuit,

means responsive to the operation of said key and controlled overcircuits including the tip and ring conductors of the first mentionedlink circuit and sleeve conductors of the second mentioned link circuitfor disconnecting the repeater from the connection between the lines andagain including the first mentioned link circuit in the connectionbetween the lines.

4. In atelephone system, lines, a link circuit for establishing aconnection between two of said lines, a second link circuit forconnecting said lines, a repeater, means in said second link circuit forconnecting the repeater in the connection between said lines, a sourceof signaling current, means controlled from said first link circuit fortransmitting signal currents from said source to said lines and forexcluding said repeater from the connection between said lines.

5. In a telephone system, lines, a link circuit for establishingconnections between two of said lines, a second link circuit forconnecting said lines, a repeater associated with said second linkcircuit, means responsive to the connection of said second link circuitto said lines for automatically excluding the first mentioned linkcircuit from the connection between said lines, means in said secondlink circuit for including said repeater in the connection between saidlines, a key in said first mentioned link circuit, a source of signalingcurrent, and

means responsive to the operation of said key and controlled overcircuits including the tip and ring conductors of the first mentionedlink circuit and sleeve conductors of the second mentioned link circuitfor disconnecting the repeater from the connection be tween the lines,for again including the first link circuit in the connection between thelines and for establishing a connection from said signaling source tosaid line.

6. In a telephone system, lines, a link circuit for establishingconnections between two of said lines, a second link circuit torconnecting said lines, a repeater associated with said second mentionedlink circuit and normally disconnected therefrom, means in said secondmentioned link circuit tor connecting said repeater in the connectionbetween said lines, a signal device in said first mentioned linkcircuit, and means rcspon sive to alternating current signals incomingover a line to said second mentioned link circuit for actuating saidsignal device in the first mentioned link circuit.

7. In a telephone circuit, lines, a link circuit for establishing aconnection between two of said lines, a second link circuit forconnecting said lines, a repeater associated with said second mentionedlink circuit, means in said second link circuit for including saidrepeater in the connection between said lines, an alternating currentsource associated with said second link circuit, a signal device in saidfirst mentioned link circuit, and means in said second link circuitresponsive to alternating current signals incoming over a line fortransmitting a signal. from said alternating current source to said.first mentioned link circuit, and means in said first mentioned linkcircuit responsive to said signaling current for actuating said signaldevice.

8. In a telephone system, lines, a link circuit for establishing aconnection between two of said lines, a second link circuit forconnecting said lines, a repeater associated with said second mentionedlink circuit and normally disconnected therefrom, means in said secondmentioned link circuit tor con necting said repeater in the connectionbetween said lines, a signal device in said first mentioned linkcircuit, and means responsive to alternating current signals incomingover a line to said second mentioned link circuit for actuating saidsignal device and for disabling said repeater.

9. In a telephone circuit, lines, a link circuit for establishing aconnection between two of said lines, a second link circuit forconnecting said lines, a repeater associated with said second mentionedlink circuit and normally disconnected therefrom, means in said secondmentioned link circuit for com nesting said repeater in the connectionbetween said lines, an operators telephone set,

means for connecting said telephone set to said lines, a source ofsignallng current,

means for transmitting current from said source to said lines, a-slgnaldevice in said first mentioned link circuit, means responsive toalternating current signals incoming over said lines for actuating saidsignal device, and means for disabling the repeater responsive to theactuation of the means for connecting the telephone set and responsive.to the actuation of the means for transmitting signaling current overthe lines and responsive to alternating current signals incoming overthe lines to actuate said signal device.

In witness whereof, I hereunto subscribe my name this 16th day of March,A. D. 1926.

HAROLD J. FISHER.

